Total incineration process

ABSTRACT

Waste water is cycled through a wet scrubber and a fluid bed incinerator fed by a first combustion chamber so that the waste water is concentrated in the wet scrubber as it removes solid particles from gases introduced from the fluid bed incinerator, the fluid bed incinerator removing inorganic solids at relatively low temperatures, gaseous effluent from the wet scrubber and hot gases from a second combustion chamber passing to a second firing chamber to oxidize organic matter entrained in the gaseous effluent at a higher temperature, the gaseous effluent passing through a steam boiler for heat recovery.

United States Patent [72] Inventor John Lambiris New York, NY. [21]Applv No. 852,351 {22] Filed Aug. 22, 1969 [45] Patented Aug. 24, 1971731 Assignees Richard George Reimus Warren, Pa. Struthers Scientific andInternational Corporation [32] Priority Aug. 27, 1968 [33] Great Britain[31] 40870/68 5 4] TOTAL INCINERATION PROCESS 6 Claims, 1 Drawing Fig.

[S2] U.S.Cl 110/10 [51] Int. Cl F23g 5/02 [50] Field ofSeai-ch .J. 110/7, 8, l0

Primary ExaminerKenneth W. Sprague Attorney-William A. Drucker ABSTRACT:Waste water is cycled through a wet scrubber and a fluid bed incineratorfed by a first combustion chamber so that the waste water isconcentrated in the wet scrubber as it removes solid particles fromgases introduced from the fluid bed incinerator, the fluid bedincinerator removing inorganic solids at relatively low temperatures,gaseous effluent from the wet scrubber and hot gases from a secondcombustion chamber passing to a second firing chamber to oxidize organicmatter entrained in the gaseous effluent at a higher temperature, thegaseous effluent passing through a steam boiler for heat recovery SIEAH1 GENERATOR WWW rmaisnui FLEL \IHAMBER 5 Patented Aug. 24, 1971 I3,601,070

( CHAMBER glgL TOTAL INCINERATION PROCESS BACKGROUND or THE INVENTIONganics such as NaCL, Na SO NaOh, etc. This invention provides aneconomical process for the treatment of such waste water.

SUMMARY OF THE INVENTION A fluid bed incinerator is fed by hot gasesfrom a first combustion chamber in which fuel is burned in an oxygenrich atmosphere and it is fed by concentrated waste water from a wetscrubber, the wet scrubber receiving waste water to scrub the hot gasesfrom the fluid bed incinerator to remove solid particles therefrom whilethe hot gases concentrate the waste water for feeding to the fluid bedincinerator, the gaseous effluent from the wet scrubber and hot gasesfrom a secondary combustion chamber being mixed at a higher temperaturein a secondary firing chamber to oxidize and thermally destroy organiccompounds therein, the gaseous effluent from the secondary firingchamber passing through a steam generator for heat recovery therefrom.

This invention uses a wet scrubber which is one of the most effectivepieces of apparatus for the removal of fine particles from a gas. Thisallows the gaseous effluent to be ultimately used in a stream generatorbecause, without the removal of the fine particles, precipitates wouldform on the heat transfer surfaces of the steam generator. In addition,the wet scrubber evaporates a large portion of the waste water by directcontact heat exchange without the use of a costly multieffectevaporation system.

The two stage incineration system of this invention allows the fluid bedto operate at a lower temperature at which organic salts do not fuse torender the fluid bed inoperable. The system then allows the subsequenthigher temperature destruction of toxic organic compounds and therecovery of heat in a steam generator.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE of the Drawing is aschematic diagram showing the apparatus of this invention and the flowtherethrough.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the Drawing, pipefeeds dilute waste water containing toxic organic compounds andinorganics to a wet scrubber 1 which may be of the tray or the cyclonictype. A counterflow of hot gases enters the wet scrubber through pipe11. The dilute waste water is vaporized and concentrated by the hotgases so that concentrated waste water flows from wet scrubber 1 throughline 12. Effluent gases leave wet scrubber l'through line 13. Theseeffluent gases are water saturated, and, for example, at a temperatureof 170 F The wet scrubber 1 serves two main purposes. First, itconcentrates the waste water by direct contact heat exchange whichobviates the need for costly multieffect heat exchange equipment withheat exchange surfaces which would have scaling problems. Thus the wetscrubber eliminates scaling problems at this stage of the process.Second, it removes all solid particles from the effluent gases leavingthe wet scrubber through pipe 13. This eliminates scaling problems at alater stage of the process as will be explained.

Line 12 leads from the wet scrubber 1 to the fluid bed incinerator 2 tospray the concentrated waster water into it. Blower l4 introduces excessair through pipe'l5 into first combustion chamber 3 to burn any suitablefuel introduced through line 16. The resulting hot gases flow fromcombustion chamber 3 through line 17 into the fluid bed incinerator tovaporize remaining water and form a fluidized bed of solid particles orgranules made from the inorganic solids in the concentrated water water.These solids in the fluidized bed are maintained at a temperature belowtheir fusion pint but high enough to drive out any organic compounds. Anexample of such a temperature would be between l,000 and 1,300" F. Thus,the sprayed concentrated waste from pipe 12 splashes in droplet form onthe fluidized bed to contact the hot gases from pipe 17 which sustainthe bed. The water is evaporated and organic compounds are driven intothe gaseous phase by evaporation, sublimation, thermal degradation, andoxidation. The inorganic solids are continually discharged from theincinerator as a dry granular product through pipe 18. The rate ofremoval of these granular salts is equal to the rate of solidsdeposition from the incinerated waste solution. The solid particles frompipe 18 may be cooled to atmospheric conditions with an air cooler orthe like and they are then ready for final disposal or use. 1

The gaseous effluent from incinerator 2 passes through pipe 19 to pipe11 to pass through the wet scrubber 1 as described. Blower 20 introducesan excess of air through pipe 21 into the second combustion chamber 4where fuel introduced through pipe 22 is burned. Combusted gases fromchamber 4 pass through line 23. Some of these combusted gases passthrough pipe 25 to enter the secondary firing chamber 5 to mix with theeffluent gases from pipe 13. At an elevated temperature of from l,600 to2,000 F. In chamber 5, organic compounds in the effluent gases arecompletely oxidized and converted to CO S0 etc. Many fuels are suitableto be combusted with excess air in chamber 4 to provide the high heatrequired in the secondary firing chamber 5.

The superheated water vapor and gaseous products from chamber 5 passthrough line 26 to a heat recovery boiler 6 for steam generation.Condensate enters line 27 to pass through steam generator 6 and leave assteam through line 28. The quality of the generated steam is equivalentto a temperature of 700 F, and a pressure of 400 p.s.i.g. If desired,the exhaust gases from steam generator 6 passing out through pipe 30 maybe scrubbed with a dilute solution of sodium carbonate if there are airpollutants present such as I-ICL, HF, P 0 S0 etc. in the exhaust gases.Any solids (inorganic salts) that might form in such a scrubber may berecycled into the system to be mixed with waste waterin pipe 10 andremoved by the fluid bed incinerator 2.

The use of the wet scrubber 1 between incinerator stages removes fineparticles from the fluid bed incinerator effluent gases to allow theoperation of the steam generator 6. If fine solids did reach the steamgenerator 6, they would precipitate on its heat transfer areas to foulit and reduce its capacity and require its more frequent shutdown andcleaning. 5

Not only does the wet scrubber l concentrate the waste water flowingfrom pipe 10, but by so doing it reduces the heat duty of the fluid bedincinerator 2 to cut its size and cost.

The two-stage incineration technique applied in this system makes itunique and independent of the nature of the organic compounds present inthe waste water. It is well known from the literature that certain toxicorganic compounds require a temperature of 1,600 to 2,000 F. for theircomplete thermal or oxidative destruction. In a one-stage incinerationstep an cineration of this process, this operational difficulty is,

bypassed. The operating temperature in the first-stage incinerator ismaintained below the fusion point but it is suffi ciently high to driveout all the organics in the gas phase. Subsequently, all the organicsare completely destroyedin the "v second-stage incinerator at anelevated temperature of 1,600 to 2,000 F. g

In this process, a heat recovery unit'6 is incorporated to generatesteam and salvage a'good portion of the fuel cost, making the wastetreatment more economical.

it should be noted that, in some applications, the combustion chambers 3and 4 could be combined with or closely associated with the fluid bedincinerator 2' and the secondary firing chamber 5.

What I claimed is:

1. Waste water treatment apparatus comprising, in combination, a wetscrubber, a fluid bed incinerator, means conducting hot gases from saidfluid bed incinerator to said scrubber and means conducting water tosaid scrubber, said wet scrubber concentrating waste water and removingsolid particles from the hot gases leaving the fluid bed incinerator,means conducting concentrated waste water from said wet scrubber to saidfluid bed incinerator to vaporize waterand gasify organics therein toform a fluidized bed of inorganics, said fluid bed incineratordischarging granules of inorganics from a fluidized bed, a hightemperature secondary firing chamber, means conducting effluent gasesfrom said wet scrubber to said secondary firing chamber to oxidizeorganics therein, and a steam generator including means conductingeffluent gases from said secondary firing chamber to said generator,said steam generator recovering waste heat from said effluent gases.

2. The combination according to claim 1 wherein the temperature in saidfluid bed incinerator is under 1,300 F. and the temperature in saidsecondary firing chamber is over l,600 F.

3. The process of treating a dilute waste water solution containingorganic and inorganic pollutants comprising the steps of:

- a. passing the dilute waste water to a wet scrubber;

b. passing effluent gases from a fluid bed incinerator into the wetscrubber counter current to the dilute waste water to havesolids removedfrom the effluent gases while the gases evaporate water by directcontact heat exchange to concentrate the waste solution;

passing the concentrated waste solution to the fluid bed incinerator tobe fluidized as a bed therein by combusted gases which evaporate waterfrom the concentrated wastes and render inorganics gaseous to providethe effluent gases passed to the wet scrubber in step (b);

. removing inorganic material from the fluidized bed of the fluid bedincinerator;

e. passing effluent gases from the wet scrubber to a second highertemperature firing chamber to be mixed with the combusted gases tooxidize and break down the organics; and

f. passing effluent gases from the second firing chamber through a steamgenerator to recover heat therefrom.

4. The process according to claim 3 wherein in step (c) combusted gasesare provided by a first combustion chamber and wherein in step (e) thecombusted gases are provided in a second higher temperature combustionchamber.

5. The process according to claim 4 wherein some of the combusted gasesfrom the second higher temperature combustion chamber are passed intosaid wet scrubber.

6. The process according to claim 3 wherein the temperature in the fluidbed incinerator is under l,300 F. and the temperature in said secondfiring chamber is over 1,600 F.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,601,070 Dated August 24, 1971 John Lambiris et a1. Inventor(s) It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

On the cover sheet "[72]" insert Richard George Reimus, Warren, Pa."[73]" cancel "Richard George Reimus, Warren, Pa.

Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents RM PO-105O (IO-69] uscoMM-Dc 00316P09 9 U S GDVIRNMENYPRINTDNG OFFICE: I'll D3-334

1. Waste water treatment apparatus comprising, in combination, a wetscrubber, a fluid bed incinerator, means conducting hot gases from saidfluid bed incinerator to said scrubber and means conducting water tosaid scrubber, said wet scrubber concentrating waste water and removingsolid particles from the hot gases leaving the fluid bed incinerator,means conducting concentrated waste water from said wet scrubber to saidfluid bed incinerator to vaporize water and gasify organics therein toform a fluidized bed of inorganics, said fluid bed incineratordischarging granules of inorganics from a fluidized bed, a hightemperature secondary firing chamber, means conducting effluent gasesfrom said wet scrubber to said secondary firing chamber to oxidizeorganics therein, and a steam generator including means conductingeffluent gases from said secondary firing chamber to said generator,said steam generator recovering waste heat from said effluent gases. 2.The combination according to claim 1 wherein the temperature in saidfluid bed incinerator is under 1,300* F. and the temperature in saidsecondary firing chamber is over 1,600* F.
 3. The process of treating adilute waste water solution containing organic and inorganic pollutantscomprising the steps of: a. passing the dilute waste water to a wetscrubber; b. passing effluent gases from a fluid bed incinerator intothe wet scrubber counter current to the dilute waste water to havesolids removed from the effluent gases while the gases evaporate waterby direct contact heat exchange to concentrate the waste solution; c.passing the concentrated waste solution to the fluid bed incinerator tobe fluidized as a bed therein by combusted gases which evaporate waterfrom the concentrated wastes and render inorganics gaseous to providethe effluent gases passed to the wet scrubber in step (b); d. removinginorganic material from the fluidized bed of the fluid bed incinerator;e. passing effluent gases from the wet scrubber to a second highertemperature firing chamber to be mixed with the combusted gases tooxidize and break down the organics; and f. passing effluent gases fromthe second firing chamber through a steam generator to recover heattherefrom.
 4. The process according to claim 3 wherein in step (c)combusteD gases are provided by a first combustion chamber and whereinin step (e) the combusted gases are provided in a second highertemperature combustion chamber.
 5. The process according to claim 4wherein some of the combusted gases from the second higher temperaturecombustion chamber are passed into said wet scrubber.
 6. The processaccording to claim 3 wherein the temperature in the fluid bedincinerator is under 1,300* F. and the temperature in said second firingchamber is over 1,600* F.